Why Hasn't Hollywood Made a Movie About This Myth Yet?

Some of the greatest fantasy and science fiction movies are based on stories from myth. But there are so many great mythological tales that Hollywood hasn't tackled yet. What's the one mythical story or creature you are dying to see in a giant CGI mega-blockbuster?

For our purposes here, let's define "myth" as broadly as possible, so we can include modern myths as well as mythical tales from religion. Links, pictures, and video clips please! Give us the myth in full color!